AFM voltage readings different?

[Evilsmith]

In my quest to resolve my M20 running rich, hesitating, and dying after revving, I am attempting to test two AFM's that I have.

I hooked up a 9V battery to the first two spade connections to simulate the car voltage, then moved the barn door. These are the two readings I got from the AFM's:

AFM #1 = low .396v, mid 4.00v, high 7.24v

AFM #2 = low .128v, mid .870v, high 5.85v

Both temperature sensors in the AFM's tested within tolerance. However, im not sure if either of these readings are optimal because I do not have a gauge from a KNOWN good working AFM. Does anyone know if there is a specific range and/or have readings from their own AFM that functions correctly?

[jlevie]

The AFM for an M20B25 and the AFM for an M20B27 have different curves. Are both of these units for the same engine (i.e., both have the same part number)?

[Evilsmith]

That is a very good question, and I have no idea which this is for honestly. The markings on the bottom say 1 285 501 on the bottom of both of them. One of the caps has 0280202082 and 1286615.9 on it, but Real EOM doesnt list these as part numbers.

[jlevie]

I sort of think that the number on the bottom is the same for both variants. The difference between the to is mostly in the circuit board, though the clock spring on an ETA AFM is weaker than the AFM for an M20B25. I don't remember if there's a part number on the circuit board. And I not at home to be able to check.